CN201247301Y

CN201247301Y - Apparatus for measuring isonym end of portable current transformer

Info

Publication number: CN201247301Y
Application number: CNU2008201416279U
Authority: CN
Inventors: 张斌
Original assignee: Tianjin Electric Power Corp
Current assignee: State Grid Corp of China SGCC; Tianjin Electric Power Corp
Priority date: 2008-08-18
Filing date: 2008-08-18
Publication date: 2009-05-27
Anticipated expiration: 2018-08-18

Abstract

The utility model relates to a dotted terminal measuring device of a portable current transformer, which is formed by a casing and a control circuit which is mounted in the casing, wherein a transformer and an amplifying circuit are mounted in the casing, and an ammeter, a shifting knob, a positive wiring terminal, a negative wiring terminal, a positive measuring wiring terminal, a negative measuring wiring terminal, a switch and an external power input port are arranged on the surface of the casing, four output ends of the transformer are respectively connected with the shifting knob, and the input end of the ammeter is connected with the output end of the amplifying circuit. The utility model has simple structure and low production cost, which not only can measure current transformers with different impedances, but also can effectively prevent injury to operators by arcs generated by overvoltage.

Description

Portable type current transformer end measurement mechanism of the same name

Technical field

The utility model relates to the measuring equipment of electric system, especially a kind of portable type current transformer end measurement mechanism of the same name.

Background technology

The effect of current transformer in electric system (being called for short CT) is that big electric current is become little electric current, isolate being connected the secondary circuit of relay and surveying instrument instrument and the high-pressure system of primary current, and primary current is transformed to the secondary current value of 5A or two kinds of standards of 1A.The structure of general current transformer is made up of winding, Secondary Winding, iron core and a framework of mutually insulated, housing, connection terminal etc., and its principle of work is identical substantially with transformer; And the current transformer in the electric system should carry out polarity measurement before and after handing-over and overhaul, in case when wiring that polarity is mistaken and cause the inaccurate of the malfunction in relay protection loop and measurement loop measurement data.

Generally be to adopt a joint or a few joint dry cell to be used as direct supply when polarity measurement, and respectively both positive and negative polarity received the two ends of the winding of CT, between the CT Secondary Winding, insert DC ammeter simultaneously, in order to show test results.The shortcoming of this method is: (1). dry cell belongs to chemical article, damages easily in complex environment; (2). when the needs high voltage, the operation inconvenience very when connecting a plurality of battery; (3). the voltage that the dry cell of series connection provides is limited, and when the impedance of CT was big, the electric current of secondary induction was very little, sometimes even almost nil, causes the misjudgment of CT end of the same name.

When testing the very big CT of an impedance, people adopt the two ends with a winding of CT to connect an applying direct current source apparatus, but the shortcoming of external dc power supply is: can produce very high superpotential also simultaneously with the arcing phenomenon at cut-off point when direct supply disconnects, the meeting serious threat is to the safety of testing crew.

Summary of the invention

The purpose of this utility model is to overcome the deficiencies in the prior art, provides a kind of and measures the current transformer of different impedances and effectively prevent the portable type current transformer end measurement mechanism of the same name that arcing that superpotential causes damages the operator.

The technical scheme that the utility model is taked is:

A kind of portable type current transformer end measurement mechanism of the same name, control circuit by housing and interior installation thereof constitutes, it is characterized in that: transformer and amplifying circuit are installed in housing, be provided with reometer, gear knob, positive connection terminal at surface of shell, bear connection terminal, just measuring connection terminal, negative connection terminal, switch and the external power input port measured, four output terminals of transformer connect the gear knob respectively, and the input end of reometer connects amplification circuit output end.

And, the control circuit of installing in the described housing is made up of winding DC power supply circuit and Secondary Winding metering circuit, two output terminals of a winding DC power supply circuit connect the two ends of a winding of current transformer respectively, two input ends of Secondary Winding metering circuit connect the two ends of secondary winding in current transformer respectively, winding dc power electric routing transformer wherein, rectification circuit, filtering circuit and switch are formed, the input end of transformer connects the AC power of 220V, the output terminal of transformer TA connects the input end of rectification circuit, the output terminal of rectification circuit connects the input end of filtering circuit, filtering circuit output terminal connect an end of K switch 1 and the other end of this switch connects positive connection terminal, another output terminal connects negative connection terminal, and positive connection terminal and negative connection terminal are connected the two ends of a winding of current transformer respectively; The Secondary Winding metering circuit is made up of amplifying circuit and reometer, and an input end of amplifying circuit connects is just measuring connection terminal, and another input end of amplifying circuit connects the negative connection terminal of measuring.

And described switch is that the hilted broadsword list is put switch.

And described rectification circuit is a diode bridge rectifier circuit.

And described filtering circuit is a capacitor filter.

And described amplifying circuit is the operational amplification circuit of amplified current signal.

And described reometer is the high-sensitive DC reometer that has discriminating direction.

Advantage of the present utility model and good effect are:

1. this measurement mechanism uses transformer, rectification circuit, filtering circuit that the input of alternating current 220V power supply is transformed to DC voltage, disconnects the injury of the arcing at the switch place that superpotential that direct supply produces causes to the operator when effectively having avoided the big impedance current transformer of conventionally test.

2. the transformer of this measurement mechanism is many taps no-load voltage ratio transformer, by with being used of gear knob, make transformer that many grades of voltages outputs be arranged; And simple in structure, be suitable for measuring current transformer with different impedances.

3. the amplifying circuit of this measurement mechanism carries out processing and amplifying with the feeble signal in the Secondary Winding, outputing to reometer then shows, and reometer adopts sensitivity higher and have the DC ammeter of discriminating direction, can judge very intuitively current transformer once, the end of the same name of Secondary Winding.

4. this measurement mechanism is simple in structure, with low cost, not only can measure the current transformer of different impedances, and can effectively prevent the injury that arcing that superpotential causes causes the operator.

Description of drawings

Fig. 1 is an equivalent circuit diagram of the present utility model.

Fig. 2 is a structural representation of the present utility model.

Fig. 3 is the equivalent circuit diagram of the utility model application example.

Embodiment

Below in conjunction with embodiment, the utility model is further specified, following embodiment is illustrative, is not determinate, can not limit protection domain of the present utility model with following embodiment.

A kind of portable type current transformer end measurement mechanism of the same name, as shown in Figure 1, form by a winding DC power supply circuit (dotted portion among the figure) and Secondary Winding metering circuit, two output terminals of a winding DC power supply circuit connect the two ends of a winding of current transformer respectively, two input ends of Secondary Winding metering circuit connect the two ends of secondary winding in current transformer respectively, winding dc power electric routing transformer TA wherein, rectification circuit, filtering circuit and K switch 1 are formed, the input end of transformer TA connects the AC power of 220V, the output terminal of transformer TA connects the input end of rectification circuit, the output terminal of rectification circuit connects the input end of filtering circuit, filtering circuit output terminal connect an end of K switch 1 and the other end of this K1 switch connects positive connection terminal, another output terminal connects negative connection terminal, and positive connection terminal and negative connection terminal are connected the two ends of a winding of current transformer respectively;

The Secondary Winding metering circuit is made up of amplifying circuit and reometer, and the input end of reometer connects the output terminal of amplifying circuit, and an input end of amplifying circuit connects is just measuring connection terminal, and another input end of amplifying circuit connects the negative connection terminal of measuring.

K switch 1 is that the hilted broadsword list is put switch, and rectification circuit is a diode bridge rectifier circuit, and filtering circuit adopts capacitor filter, and mu balanced circuit uses the voltage stabilizing diode mu balanced circuit, and amplifying circuit is the operational amplification circuit of amplified current signal; Reometer is the high-sensitive DC reometer that has discriminating direction.

This device can adopt structure as shown in Figure 2; transformer 11; rectification circuit; filtering circuit and mu balanced circuit all are arranged in the housing 8; the amplifying circuit 12 of Secondary Winding metering circuit is arranged in the housing; the reometer 2 of Secondary Winding metering circuit is inlaid in the housing upper surface; the housing upper surface is provided with positive connection terminal 4; negative connection terminal 5; just measuring connection terminal 6; the negative connection terminal 7 of measuring; switch 10 (K1 among Fig. 1) and external power input port 9; transformer is the transformer of many taps no-load voltage ratio output in the present embodiment; its four output terminals connect four stationary contact DK1-1 of the gear knob 3 that is arranged on the housing upper surface respectively; DK1-2; DK1-3 and DK1-4; output voltage is respectively 54V; 27V; 18V and 9V; the operator obtains the input voltage of different voltage as different impedance CT after the moving contact DK1 of gear knob is connected on different stationary contacts; present embodiment also is provided with an over cap 1 that flexibly connects with housing, can avoid the damage of the reometer that is provided with on the surface of shell after this over cap closure.

Present embodiment provides a kind of layout, mounting means of each electric elements, is installed in the housing upper surface as reometer and each connection terminal, and in fact they are installed in the housing side and also are fine.

Application Example:

Measure the end of the same name of current transformer first and second winding, as shown in Figure 3

With the moving contact DK1 of gear knob be connected stationary contact DK1-1, make transformer output 54V voltage;

2. the positive connection terminal that is provided with on the housing is connected the L1 end of a winding of current transformer, the L2 that negative connection terminal is connected a winding of current transformer holds;

3. with the M1 end of just measuring connection terminal connection secondary winding in current transformer of test circuit, the negative M2 that measures connection terminal connection secondary winding in current transformer holds;

If 4. ammeter pointer positively biased during Closing Switch K1, and milliammeter pointer negative bias when disconnecting illustrate that current transformer is connected the L1 end on the positive connection terminal and is connected on the M1 end of just measuring on the connection terminal is same polarity (end of the same name).If the ammeter pointer swing is reversed polarity with above-mentioned opposite explanation L1 and M1 end.

Claims

1, a kind of portable type current transformer end measurement mechanism of the same name, control circuit by housing and interior installation thereof constitutes, it is characterized in that: transformer and amplifying circuit are installed in housing, be provided with reometer, gear knob, positive connection terminal at surface of shell, bear connection terminal, just measuring connection terminal, negative connection terminal, switch and the external power input port measured, four output terminals of transformer connect the gear knob respectively, and the input end of reometer connects amplification circuit output end.

2, portable type current transformer according to claim 1 end measurement mechanism of the same name, it is characterized in that: the control circuit of installing in the described housing is made up of winding DC power supply circuit and Secondary Winding metering circuit, two output terminals of a winding DC power supply circuit connect the two ends of a winding of current transformer respectively, two input ends of Secondary Winding metering circuit connect the two ends of secondary winding in current transformer respectively, winding dc power electric routing transformer wherein, rectification circuit, filtering circuit and switch are formed, the input end of transformer connects the AC power of 220V, the output terminal of transformer TA connects the input end of rectification circuit, the output terminal of rectification circuit connects the input end of filtering circuit, filtering circuit output terminal connect an end of K switch 1 and the other end of this switch connects positive connection terminal, another output terminal connects negative connection terminal, and positive connection terminal and negative connection terminal are connected the two ends of a winding of current transformer respectively; The Secondary Winding metering circuit is made up of amplifying circuit and reometer, and an input end of amplifying circuit connects is just measuring connection terminal, and another input end of amplifying circuit connects the negative connection terminal of measuring.

3, portable type current transformer according to claim 1 and 2 end measurement mechanism of the same name is characterized in that: described switch is that the hilted broadsword list is put switch.

4, portable type current transformer according to claim 2 end measurement mechanism of the same name, it is characterized in that: described rectification circuit is a diode bridge rectifier circuit.

5, portable type current transformer according to claim 2 end measurement mechanism of the same name, it is characterized in that: described filtering circuit is a capacitor filter.

6, portable type current transformer according to claim 2 end measurement mechanism of the same name, it is characterized in that: described amplifying circuit is the operational amplification circuit of amplified current signal.

7, portable type current transformer according to claim 1 and 2 end measurement mechanism of the same name is characterized in that: described reometer is the high-sensitive DC reometer that has discriminating direction.